/*
 * Generic map implementation.
 */
#include "hashmap.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define INITIAL_SIZE (256)
#define MAX_CHAIN_LENGTH (8)

/* We need to keep keys and values */
typedef struct _hashmap_element {
	char* key;
	int in_use;
	any_t data;
} hashmap_element;

/* A hashmap has some maximum size and current size,
 * as well as the data to hold. */
typedef struct _hashmap_map {
	int table_size;
	int size;
	hashmap_element *data;
} hashmap_map;

/*
 * Return an empty hashmap, or NULL on failure.
 */
map_t hashmap_new() {

	hashmap_map* m = (hashmap_map*) malloc(sizeof(hashmap_map));
	if (!m)
		goto err;

	m->data = (hashmap_element*) calloc(INITIAL_SIZE, sizeof(hashmap_element));
	if (!m->data)
		goto err;

	debug("Setando initial size hashing");
	m->table_size = INITIAL_SIZE;
	m->size = 0;

	return m;
	err: debug("Erro ao alocar a memoria");
	if (m)
		hashmap_free(m);
	return NULL;
}

/* The implementation here was originally done by Gary S. Brown.  I have
 borrowed the tables directly, and made some minor changes to the
 crc32-function (including changing the interface). //ylo */

/* ============================================================= */
/*  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or       */
/*  code or tables extracted from it, as desired without restriction.     */
/*                                                                        */
/*  First, the polynomial itself and its table of feedback terms.  The    */
/*  polynomial is                                                         */
/*  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0   */
/*                                                                        */
/*  Note that we take it "backwards" and put the highest-order term in    */
/*  the lowest-order bit.  The X^32 term is "implied"; the LSB is the     */
/*  X^31 term, etc.  The X^0 term (usually shown as "+1") results in      */
/*  the MSB being 1.                                                      */
/*                                                                        */
/*  Note that the usual hardware shift register implementation, which     */
/*  is what we're using (we're merely optimizing it by doing eight-bit    */
/*  chunks at a time) shifts bits into the lowest-order term.  In our     */
/*  implementation, that means shifting towards the right.  Why do we     */
/*  do it this way?  Because the calculated CRC must be transmitted in    */
/*  order from highest-order term to lowest-order term.  UARTs transmit   */
/*  characters in order from LSB to MSB.  By storing the CRC this way,    */
/*  we hand it to the UART in the order low-byte to high-byte; the UART   */
/*  sends each low-bit to hight-bit; and the result is transmission bit   */
/*  by bit from highest- to lowest-order term without requiring any bit   */
/*  shuffling on our part.  Reception works similarly.                    */
/*                                                                        */
/*  The feedback terms table consists of 256, 32-bit entries.  Notes:     */
/*                                                                        */
/*      The table can be generated at runtime if desired; code to do so   */
/*      is shown later.  It might not be obvious, but the feedback        */
/*      terms simply represent the results of eight shift/xor opera-      */
/*      tions for all combinations of data and CRC register values.       */
/*                                                                        */
/*      The values must be right-shifted by eight bits by the "updcrc"    */
/*      logic; the shift must be unsigned (bring in zeroes).  On some     */
/*      hardware you could probably optimize the shift in assembler by    */
/*      using byte-swap instructions.                                     */
/*      polynomial $edb88320                                              */
/*                                                                        */
/*  --------------------------------------------------------------------  */

static unsigned long crc32_tab[] = { 0x00000000L, 0x77073096L, 0xee0e612cL,
		0x990951baL, 0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
		0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL,
		0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L,
		0xf3b97148L, 0x84be41deL, 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L,
		0x83d385c7L, 0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
		0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L,
		0x4c69105eL, 0xd56041e4L, 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L,
		0xd20d85fdL, 0xa50ab56bL, 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L,
		0xacbcf940L, 0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
		0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L,
		0x56b3c423L, 0xcfba9599L, 0xb8bda50fL, 0x2802b89eL, 0x5f058808L,
		0xc60cd9b2L, 0xb10be924L, 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL,
		0xb6662d3dL, 0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
		0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L,
		0x0f00f934L, 0x9609a88eL, 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL,
		0x91646c97L, 0xe6635c01L, 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L,
		0xf262004eL, 0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
		0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL,
		0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL,
		0xa3bc0074L, 0xd4bb30e2L, 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL,
		0xd3d6f4fbL, 0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
		0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL,
		0x270241aaL, 0xbe0b1010L, 0xc90c2086L, 0x5768b525L, 0x206f85b3L,
		0xb966d409L, 0xce61e49fL, 0x5edef90eL, 0x29d9c998L, 0xb0d09822L,
		0xc7d7a8b4L, 0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
		0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL, 0xead54739L,
		0x9dd277afL, 0x04db2615L, 0x73dc1683L, 0xe3630b12L, 0x94643b84L,
		0x0d6d6a3eL, 0x7a6a5aa8L, 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L,
		0x7d079eb1L, 0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
		0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L,
		0x89d32be0L, 0x10da7a5aL, 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L,
		0x17b7be43L, 0x60b08ed5L, 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L,
		0x4fdff252L, 0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
		0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L, 0xdf60efc3L,
		0xa867df55L, 0x316e8eefL, 0x4669be79L, 0xcb61b38cL, 0xbc66831aL,
		0x256fd2a0L, 0x5268e236L, 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L,
		0x5505262fL, 0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
		0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L,
		0xec63f226L, 0x756aa39cL, 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL,
		0x72076785L, 0x05005713L, 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL,
		0x0cb61b38L, 0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
		0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL,
		0xf6b9265bL, 0x6fb077e1L, 0x18b74777L, 0x88085ae6L, 0xff0f6a70L,
		0x66063bcaL, 0x11010b5cL, 0x8f659effL, 0xf862ae69L, 0x616bffd3L,
		0x166ccf45L, 0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
		0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL,
		0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L,
		0x47b2cf7fL, 0x30b5ffe9L, 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L,
		0x24b4a3a6L, 0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
		0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L,
		0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL };

/* Return a 32-bit CRC of the contents of the buffer. */

unsigned long crc32(const unsigned char *s, unsigned int len) {

	unsigned int i;
	unsigned long crc32val;

	crc32val = 0;
	for (i = 0; i < len; i ++) {
		crc32val = crc32_tab[(crc32val ^ s[i]) & 0xff] ^ (crc32val >> 8);
	}

	return crc32val;
}

/*
 * Hashing function for a string
 */
unsigned int hashmap_hash_int(hashmap_map * m, char* keystring) {

	unsigned long key = crc32((unsigned char*)(keystring), strlen(keystring));

	/* Robert Jenkins' 32 bit Mix Function */
	key += (key << 12);
	key ^= (key >> 22);
	key += (key << 4);
	key ^= (key >> 9);
	key += (key << 10);
	key ^= (key >> 2);
	key += (key << 7);
	key ^= (key >> 12);

	/* Knuth's Multiplicative Method */
	key = (key >> 3) * 2654435761;

	int result = key % m->table_size;

	return result;
}

/*
 * Return the integer of the location in data
 * to store the point to the item, or MAP_FULL.
 */
int hashmap_hash(map_t in, char* key) {
	int curr;
	int i;

	/* Cast the hashmap */
	hashmap_map* m = (hashmap_map *) in;

	/* If full, return immediately */
	if (m->size >= (m->table_size/2))
		return MAP_FULL;

	/* Find the best index */
	curr = hashmap_hash_int(m, key);

	/* Linear probing */
	for (i = 0; i< MAX_CHAIN_LENGTH; i++) {
		if (m->data[curr].in_use == 0)
			return curr;

		if (m->data[curr].in_use == 1 && (strcmp(m->data[curr].key, key)==0))
			return curr;

		curr = (curr + 1) % m->table_size;
	}

	return MAP_FULL;
}

/*
 * Doubles the size of the hashmap, and rehashes all the elements
 */
int hashmap_rehash(map_t in) {
	int i;
	int old_size;
	hashmap_element* curr;

	/* Setup the new elements */
	hashmap_map *m = (hashmap_map *) in;
	hashmap_element* temp = (hashmap_element *) calloc(2 * m->table_size,
			sizeof(hashmap_element));
	if (!temp)
		return MAP_OMEM;

	/* Update the array */
	curr = m->data;
	m->data = temp;

	/* Update the size */
	old_size = m->table_size;
	m->table_size = 2 * m->table_size;
	m->size = 0;

	/* Rehash the elements */
	for (i = 0; i < old_size; i++) {
		int status;

		if (curr[i].in_use == 0)
			continue;

		status = hashmap_put(m, curr[i].key, curr[i].data);
		if (status != MAP_OK)
			return status;
	}

	free(curr);

	return MAP_OK;
}

/*
 * Add a pointer to the hashmap with some key
 */
int hashmap_put(map_t in, char* key, any_t value) {

	int index;
	hashmap_map* m;

	/* Cast the hashmap */
	m = (hashmap_map *) in;

	/* Find a place to put our value */
	debug("Find a place to put our value");
	index = hashmap_hash(in, key);
	while (index == MAP_FULL) {
		debug(".");
		if (hashmap_rehash(in) == MAP_OMEM) {
			debug("MAP_OMEM");

			return MAP_OMEM;
		}
		index = hashmap_hash(in, key);
	}

	/* Set the data */
	debug("Set the data");
	m->data[index].data = value;
	m->data[index].key = key;
	m->data[index].in_use = 1;
	m->size++;

	debug("MAP_OK");

	return MAP_OK;
}

/*
 * Get your pointer out of the hashmap with a key
 */
int hashmap_get(map_t in, char* key, any_t *arg) {

	int curr;
	int i;
	hashmap_map* m;

	/* Cast the hashmap */
	m = (hashmap_map *) in;

	/* Find data location */
	curr = hashmap_hash_int(m, key);

	/* Linear probing, if necessary */
	for (i = 0; i < MAX_CHAIN_LENGTH; i++) {

		debug(".");

		int in_use = m->data[curr].in_use;

		if (in_use == 1) {

			debugs("key: ", m->data[curr].key);

			if (strcmp(m->data[curr].key, key)==0) {
				*arg = (m->data[curr].data);
				lastMethodName();
				return MAP_OK;
			}
		}

		curr = (curr + 1) % m->table_size;
	}

	*arg = NULL;

	lastMethodName();

	/* Not found */
	return MAP_MISSING;
}

/*
 * Iterate the function parameter over each element in the hashmap.  The
 * additional any_t argument is passed to the function as its first
 * argument and the hashmap element is the second.
 */
int hashmap_iterate(map_t in, PFany f, any_t item) {
	int i;

	/* Cast the hashmap */
	hashmap_map* m = (hashmap_map*) in;

	/* On empty hashmap, return immediately */
	if (hashmap_length(m) <= 0)
		return MAP_MISSING;

	/* Linear probing */
	for (i = 0; i< m->table_size; i++)
		if (m->data[i].in_use != 0) {
			any_t data = (any_t) (m->data[i].data);
			int status = f(item, data);
			if (status != MAP_OK) {
				return status;
			}
		}

	return MAP_OK;
}

/*
 * Remove an element with that key from the map
 */
int hashmap_remove(map_t in, char* key) {
	int i;
	int curr;
	hashmap_map* m;

	/* Cast the hashmap */
	m = (hashmap_map *) in;

	/* Find key */
	curr = hashmap_hash_int(m, key);

	/* Linear probing, if necessary */
	for (i = 0; i<MAX_CHAIN_LENGTH; i++) {

		int in_use = m->data[curr].in_use;
		if (in_use == 1) {
			if (strcmp(m->data[curr].key, key)==0) {
				/* Blank out the fields */
				m->data[curr].in_use = 0;
				m->data[curr].data = NULL;
				m->data[curr].key = NULL;

				/* Reduce the size */
				m->size--;
				return MAP_OK;
			}
		}
		curr = (curr + 1) % m->table_size;
	}

	/* Data not found */
	return MAP_MISSING;
}

/* Deallocate the hashmap */
void hashmap_free(map_t in) {
	hashmap_map* m = (hashmap_map*) in;
	free(m->data);
	free(m);
}

/* Return the length of the hashmap */
int hashmap_length(map_t in) {
	hashmap_map* m = (hashmap_map *) in;
	if (m != NULL)
		return m->size;
	else
		return 0;
}
